Strain effects on photoluminescence polarization of InAs/GaAs self-assembled quantum dots

We have investigated the photoluminescence (PL) polarization properties of InAs/GaAs self-assembled quantum dots (QDs). An 8 nm InxGa1-xAs capping layer was overgrown on InAs QDs in order to modify the strain distribution in the dots. TE and TM mode PL polarizations of samples with capping layer indium composition of x = 0 and x = 0.13 were detected and analyzed. The TE/TM ratio shows heavy-hole dominant optical transition for samples with x = 0. On the other hand, samples with x = 0. 13 show light-hole dominant optical transition. These results indicate valence band state inversion through in-plane strain distribution dependent on the capping layer composition.